1. Field
The present disclosure relates to an automatic transmission controller.
2. Description of the Related Art
To improve driving performance and drivability, the number of gear ratios of an automatic transmission for an automobile is being increased. In general, an automatic transmission includes engagement mechanisms, such as planetary gear mechanisms, clutches, and brakes. The gear ratio of the automatic transmission is changed by changing the power transmission path by using the engagement mechanisms. Such an automatic transmission includes a torque converter (starting mechanism) that is disposed between a drive source and a driving wheel of a vehicle and that transmits rotational power from the drive source to the driving wheel.
In recent years, automatic transmission controllers that perform so-called “idling reduction control” when a vehicle stops have been increasingly used.
When a vehicle that performs idling reduction control stops on, for example, an uphill slope, backward movement of the vehicle can be prevented by using a creep torque of the torque converter if the starting response of the engine is sufficiently good. However, if the inclination angle of the slope is considerably large, it is not possible to prevent backward movement. Moreover, the driver may be unexpectedly inconvenienced because the engine stops when idling reduction control is performed.
For example, Japanese Unexamined Patent Application Publication No. 2012-46182 describes a controller that detects the inclination angle of a position at which a vehicle stops. The controller increases a braking force when the vehicle stops on a slope with consideration that stopping the engine leads to a decrease in the braking force.
Japanese Unexamined Patent Application Publication No. 2012-47147 describes a controller that uses a sensor for detecting the inclination angle of a slope so that a vehicle does not move down the slope when idling reduction control is performed.